As there are no updates available at all, from the Nu Vision website it supports the above statement.

Did you manually try to update the tab? If so that is why you are getting the unknown error message.

They must have 'customized' the OS to suit their requirements and in doing so have disabled or removed a part of the system update procedure for the reason that they do not want the OS updated from its' present version. They should really have removed the system update option or grayed it out so that users could not see or use the option at all but that is their concern.

My experience with NuVision tablets have been nothing but shameful and downright despicable I purchased the tablet about a year ago for $180 and the day I bought it it never powered on your charge I had it fixed recently for $90 only to realize later that it's not even worth half of that it is so slow even as a brand new tablet fresh out of the box and recently fixed also the fact that NuVision removed the ability to update your device under the settings menu in most if not all Androids is ludicrous to me if not the whole world why would a company limit its ability to the upgraded knowing that this will only diminish the value of the tablet immediately after purchase good basic concept but not allowing users to update their device baffles me to the point of which I've never experienced in my life even to the point of writing this much on a Blog no one will ever read but just in case they do I will warn them to never purchase anything made by NuVision were Company by NuVision I tried reaching out to them when my device when I start from day one there are nothing but combative and unhelpful would not offer warranty service or reimbursement with receipt two days after purchase you might ask why I paid $90 to have it fixed well I paid $180 for it and I figured it was going to be worth it because pallets of that caliber AKA Samsung Galaxy Tab a xcetera all wonderful I've even bought an Acer tablet from Office Depot for $46 that blows the NuVision 10.1 inch HD tablet out of the water